This article is from the WeChat public account: Neural Reality (ID: goodness) , author: ANTHES, from FIG title: IC photo
Microglia go to the front
Almost two decades ago, Donna Jackson Nakazawa’s immune system made a mistake in judging (Donna Jackson Nakazawa) on her own body. An attack was launched. The white blood cells that should have resisted the invading pathogen turned to attack her nerves, destroying the lipid insulator that assists in signal transmission in the outer layer of the neuron. Zhongze suffered from a rare autoimmune disease: Guillain-Barre syndrome (Guillain-Barré syndrome) . The condition caused muscle cramps and temporarily disabled the journalist and writer from walking.
However, in addition to her physical symptoms, Nakazawa noticed that her thinking seemed to be a little bit wrong. She developed severe anxiety and began to experience annoying memory errors, even forgetting how to tie her daughter’s shoes. “As my body changed, there seemed to be a substantial change in my brain-I can’t shake this idea.” In her new book “Angels and Assassins: Small Cerebellar Cells That Change the Process of Medicine” (The Angel and the Assassin: The Tiny Brain Cell That Changed The Course of Medicine) , Nakazawa wrote.
“Angels and Assassins: Small Cerebellar Cells That Change the Process of Medicine”, image source: Amazon.com
At the time, doctors couldn’t explain exactly what happened to her. For a long time, scientists have thought that the brain has “immune privileges” and blocks the peripheral immune system. Therefore, the excessively active white blood cells of Zhongze should not cause those cognitive symptoms. However, over the past decade, a series of amazing discoveries about microglia (microglia) have upset this understanding. Research has confirmed that this tiny brain cell that has been neglected for a long time is the brain’s own immune system and plays an important role in shaping the neural network. The book Angels and Assassins inspires microglia and their potential to rebuild medicine.
Nakazawa has a very clear description of the complex fields of immunology and neuroscience. The success of scientific research is unpredictable. The stories about cutting-edge researchers and patients who may benefit from it are intertwined. Refreshing. Nakazawa believes: “We are on the cusp of subverting psychiatry: microglia shape our brain and have a huge impact on our mental health throughout life-this new understanding covers the entire field of medicine and will certainly Shaping our understanding of psychiatry. “
In brain cells, those responsible for sending and receiving electrochemical signalsNeurons have always been considered protagonists. Other brain cells are collectively referred to as “glial cells” (glial cells) , which have long been reduced to supporting roles. “Glial cells are logistical groups, and they serve the needs of neurons just like the stars’ followers,” Nakazawa wrote.
Among several types of glial cells, the role of microglia is the most inconspicuous. They are brain cleaners, paying close attention to injuries and infections, removing pathogens, malformed proteins, and dead cells. “They are low-brained garbage movers,” Nakazawa wrote, “robot-like cleaners. That’s all.”
Garden and executioner, the difference between the front lines
However, with the advancement of imaging technology at the beginning of this century, scientists have begun to further study the exact behavior of microglia. They found that microglia are not sitting idle all day long-on the contrary, they are very proactive. “Under a high-resolution microscope, a single microglia is like an elegant branch, with many slender branches.” The book wrote, “The branches are swirling around in the brain, searching, searching, Do n’t miss even the slightest distress signal. “
Researchers soon made a more amazing discovery. Neuroscientists have learned that the developing brain will form excess synapses (connection between neurons) and gradually eliminate irrelevant connections during development However, the mechanism of this synaptic pruning is not clear. Until 2012, Beth Stevens and his team reported an incredible thing: Microglial cells swallow extra synapses, especially those that are underutilized < / strong>.
“A single microglia is like an elegant branch with many slender branches”, image source: biologywise.com
This is an important task: by eliminating weak and idle synapses, microglia promote healthy brain development. At the same time, Stevens and other scientists began to think about what would happen if the process went wrong—just as white blood cells sometimes mistakenly attack healthy tissue. Maybe, Nakazawa wrote, “Like white blood cells, microglia are not always correct. In case, they not only trim damaged or aged neurons, but also mistakenly engulf and destroy healthy synapses. What happened? “
From Alzheimer’s disease to depression, many mental and neurological diseases are accompanied by synaptic loss or dysfunction. Can overactive microglia be the culprit? Research results that are still increasing in number indicate: yes. For example, research has found that active microglia levels are high in patients with depression. And, in the words of Nakazawa, “the longer the depression lasts, the more severe the destruction of microglia in the brain”. Today, microglia are thought to be associated with Alzheimer’s disease, autism, Huntington’s disease, obsessive-compulsive disorder, Parkinson’s disease, schizophrenia and other diseases.
Microglia can also be used to explain why some people with autoimmune diseases report weird cognitive symptoms: for example, Nakazawa with Guillain-Barre Syndrome. A few years ago, scientists found lymphatic vessels in the meninges that envelope and protect the brain to transport white blood cells within the body. These lymphatic vessels may directly connect the peripheral immune system with the brain-experts have insisted there is no connection.
This finding means that when the body’s immune response increases, signals can be transmitted through these lymphatic vessels and trigger microglia’s aggressive behavior. ( In addition to phagocytosing synapses, activated microglial cells also process a large number of compounds that cause neuroinflammation and damage healthy neurons and brain tissue. From infection to chronic stressA variety of things can cause microglial abnormalities; scientists have documented a range of microglial abnormalities in people with immune-related disorders, including patients with lupus, multiple sclerosis, and Crohn’s disease. “This shows that the insurmountable boundary that has long been entrenched in mental and physical health does not exist,” Nakazawa wrote.
These discoveries offer new therapeutic opportunities. Nakazawa wrote in the book that researchers are working on a series of methods to “soothe overactive microglia” and “make them work properly and become the guardian angel of the brain, not the blind assassin.” More unconventional than others. Nakazawa interviewed several patients undergoing experimental treatment. Among them, there is hope that transcranial magnetic stimulation (transcranial magnetic stimulation) can relieve depression and Katie, who is panic disorder, and Laila, who is suffering from Crohn’s and OCD, is trying a “fast food-like diet” designed to reduce immune activity. There are also exploratory studies on immunotherapy, neurofeedback, vagus nerve stimulation, and even hallucinogens.
* Translator’s Note: Transcranial magnetic stimulation, a non-invasive brain stimulation technology, uses induced magnetic fields to generate induced currents in specific areas of the brain. This has caused a series of physiological and biochemical reactions; it is a medical treatment method and has also been used in scientific experiments in areas such as cognitive psychology.
It cannot be overemphasized, and the prospect is still promising
These possibilities are really exciting and make us want to believe that science has cracked a large number of mysterious and intractable disease codes, but our understanding of microglia is far from exhaustive, so it ca n’t be too far away, nor can we Gives a cell too much explanatory power.
“Too much emphasis on microglial activity and the biological mechanisms that form brain disease can lead to bioreductionism and over-medicalization,” Nakazawa wrote, “and devalues the close relationship between psychology and human consciousness. Association. “
In addition, our bodies and brains are extremely complex, and microglia are just one part of this intricate physiological system. 
Donna Jackson Nakazawa, picture source: donnajacksonnakazawa.com
She also gave a compelling case to show that our new understanding of microglia has changed. “The new classification method classifies mental disorders and neurodegenerative diseases into both microglia and immune system disorders. This is beneficial for future research and understanding.”
Nakazawa proposed that we completely separate mental and neurological diseases from other physiological diseases, and think that they are not “legitimate” in a sense-not really “illness”. This situation has been going on for too long. And if new research on microglial cells can help to overturn this presumption, it is something to celebrate in itself.
Please poke the link: https://undark.org/2020/01/31/angel-assassin-book-review/
This article comes from WeChat public account: neural reality (ID: neureality) , author: ANTHES